Method for stabilizing motor fuel against gum formation



R. E. BURK May 25, 1937.

METHOD FOR STABILIZING MOTOR FUEL AGAINST GUM FORMATION Filed Dec. 23,1935 y INVENTOR.

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Patented May 25, 1937 UNITED STATES PATENT OFFICE METHOD FOR.STABILIZING MOTOR FUEL AGAINST GUM FORMATION Robert E. Burk, Cleveland,Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, acorporation of Ohio In the customary methods of producing motor fuel bycracking petroleum, there is a formation of unstable gum-formingbyproducts which subsequently require particular treatment if theirresultsare to be avoided. Even this is not always Wholly effective. Ihave now found however, how,-

to produce motor fuel by cracking without the undue formation ofgum-components.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described, andparticularly pointed out in the claims, the following de- Scription andthe annexed drawing setting forth in detail an illustrative embodimentof the in- 25 vention, this being indicative however, of but one of thevarious ways in which the principle of the invention may be employed. l

In said annexed drawing:- The sole figure is a semi-diagrammatic eleva-20 tional view of apparatus contemplated in the inlVention.

Cracking stock as desired, for example gas oil, is subjected to crackingwhich for desirable efciency may be represented by subjection first 25to a heating zone 2 and then to a digesting zoneV 3. From the digestingzone, in accordance with the present invention, the highly heatedproducts proceed to a high pressure zone or drum 4 in which ahighpressure is maintained and an ele- 30 vated temperature. Forinstance, the pressure may be ZOO-1500 pounds per square inch and thetemperature 60G-850 F. From the high pressure Zone 4, the products passthrough a pressuredrop valve 5 to a tar separator 6. Vapors dis- 35engaged here proceed on through the fractionating zones l, 8, andvarious cuts are taken off, and finally the motor fuel hydrocarbons passfrom condenser 9 to receiver I II which may have a pressure of 0-200pounds per square inch. From 40 the receiver I0, all or a portion of themotor fuel condensate is returned by pump I I to again enter the highpressure high temperature zone 4, there `to mix with the otherhydrocarbons in highly heated condition, and under favorable conditionsfor inter-reaction. The motor fuel then finally taken off after thevapors have proceeded through the separator 6 and the fractionatingzones 1, 8, and condenser 9, is found to have its gum-form- 5 ingtendency checked, due apparently to reaction by the sensitivegum-forming parent substances. The motor fuel may be recycled one ormore times as desired back through the high pressure zone 4.

As a further refinement of the invention, tarry 'i0 material or the likeWithdrawn from separator 6, or from the bottom of the high pressure zone4 may be subjected to a vacuum stripping zone I2, from whence the vaporsproceed through fractionating zones I3, I4, each taking out itsrespective fraction, and the motor fuel hydrocarbons as finallycondensed in zone I5 proceed to receiver I6, all this portion of thesystem being under reduced pressure from the vacuum line II on the gasdraw-off. Again, all or a portion of the motor fuel hydrocarbons may beforwarded by a pump I8 back to recycle through the high pressure zone 4,one or more times as desired.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in the following claim, or the equivalent of such, beemployed.

I therefore particularly point out and distinctl claim as my inventiom-A process of gum-stabilizing motor fuel, which comprises heatingheavyhydrocarbons to cracking temperature, digesting the hot hydrocarbonsunder pressure in an unheated zone, passing the products to a furtherpressure zone without temperature increase, maintaining the productsfrom such pressure zone in uid state, then dropping the pressure,fractionating gasoline from the products, and passing such gasolineagain through said pressure zone to contact with the hot freshly crackedfluid products.

ROBERT E. BURK.

